Cannabinoids, including marijuana's main psychoactive ingredient, Δ9-tetrahydrocannabinol (THC), are known to have cardiovascular effects, an important component of which is a decrease in arterial blood pressure (hypotension). The endogenous cannabinoid anandamide also elicits hypotension, which is mediated by the CB1 cannabinoid receptor, the same receptor that mediates the psychotropic effects of marijuana and THC. Indeed, efforts to develop synthetic cannabinoid analogs as antihypertensive agents have been hampered by the fact that the psychotropic and hypotensive actions could not be separated. Because CB1 receptors in the brain mediate the psychological effects of marijuana, treating a chronic disease with a drug that directly stimulates CB1 receptors may be unacceptable.
U.S. Pat. No. 6,562,846 to Sit et al. (Sit) discloses compounds and pharmaceutical compositions purported to be useful for inhibiting FAAH. Sit proposes that inhibitors of FAAH can be used to increase the levels of endogenous cannabinoids and Sit proposes that such an increase in endogenous cannabinoids may be useful for treating certain disorders.
The FAAH inhibitors described by Sit generally are bisarylimidazole derivatives. One specific example has the formula:

U.S. Pat. No. 6,462,054 to Boger describes FAAH inhibitors having an α-keto heterocyclic group. A typical representative of Boger's inhibitors is the α-keto oxazolopyridine derivative of oleic acid:
Boger proposes that such compounds can be used to treat sleep disorders, such as by inducing sleep. However, previously proposed FAAH inhibitors, including those proposed by Boger, lack in vivo activity despite exhibiting inhibition of FAAH in vitro. Therefore, there is a need for new FAAH inhibitors having in vivo activity.